A brief introduction to commonly used high-frequency electromagnetic field simulation software
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Commonly used high-frequency electromagnetic field simulation software include the following: Ansoft HFSS, Designer, Emsenble. Ansoft has always used FEM (finite element method), and HFSS has an absolute market share in mainland China. It has always been believed that small-scale simulation is good, but large-scale simulation is not. Over the past year, we have been committed to overturning this impression. In terminal simulation, we believe that the network parameters are relatively correct, but the field parameters are sometimes not so satisfactory. For example, when modeling a dipole, a lot of manual intervention network division is added to most of the key parts, but the gain and pattern beam angle width are quite different. Mobile phone antenna simulation often has an efficiency of more than 100%. In version 9.1, we had to add the realized gain option to the results, and give you a discount on the value of the gain option CST's Microwave Studio has always been known as FDTD, but it is actually the time-domain integration method (FITD). Of course, it is not different in principle. Unlike the FEM method, FDTD or FITD first calculates in the time domain, uses a wide spectrum excitation signal (square wave or Gaussian wave) to excite the model, calculates in the time domain and then inverts to the frequency domain. The network parameters and field parameters of the system are basically obtained after inversion. The characteristic is that it can calculate a very large bandwidth result, without the need to split the large bandwidth and simulate it separately like using ANSoft. In the CST calculation process, since there is no matrix inversion process in the FEM calculation process, the calculation time and the number of grids grow linearly, while the FEM is an exponential growth relationship. CST's MWS has begun to have a large and small grid nesting technology since version 4.3, which refines the hexahedral grid on the surface to approximate the surface. This is not available in other FDTD packages. The biggest problem of CST's MWS is that it is not as fool-proof as ANSoft. Many parameters are not easy to understand even after reading the help. If you have a deep understanding of the internal details of MWS, you can probably make a perfect simulation without convergence at one time. We have used the exact same model to run in ansoft and CST respectively. As a result, the CST result of the dual-band antenna is higher in low frequency than the ansoft result. And lower in high frequency than the ansoft result. However, the field parameters are much more reliable. A model with plastic shell parameters, batteries, shielding cover and other components, the antenna is 40% to 50% more realistic at the resonance point. South Korea uses CST, and few people use ansoft. Zeland IE3D, MoM method. IE3D is probably the best commercial MoM package. The MoM principle is relatively simple and the calculation speed is extremely fast. IE3D is more suitable for 2.5D situations, such as calculating PCB or microstrip antennas, but it is not capable of calculating complex 3D structures. However, IE3D is more suitable for calculating mobile phone PIFA. It is not used for antenna project simulation, but for preliminary research in the prototype stage to study the basic characteristics of the antenna, how the antenna and PCB couple with each other, and the direction of the surface current excited on the PCB. Zeland Fidelity, FDTD method, is less famous than IE3D and not used by many people. There is no CST large and small grid nesting. I would like to add that all FDTD packages use the PML method. XFDTD is a well-known FDTD suite. It is often used in conjunction with many SAR testing hardware systems. After loading the human electromagnetic model, the SAR value can be calculated. The disadvantage is that the antenna pattern does not have a 3D display, only a 2D cross section. This disadvantage should be improved in the new version. SemCAD is also a FDTD package. It does not have many advantages over XFDTD and others. It is also used to calculate SAR. It seems to be used for system EMC calculations. IMST Empire, FDTD suite. A very good high-frequency electromagnetic field suite, made by Germans. Won many European simulation competitions, the simulation topic is a Vivalti antenna, the fastest and most accurate. But just like the Germans, it is good, but it has too many obvious flaws. The modeling method is too complicated. I didn't really learn it after three attempts. Finally, I had to give up because I didn't have time. FEKO, a software with Ansys interface, uses hybrid MoM, multi-layer fast multipole (I only know the name), geometric optics and ray tracing methods, etc. It can calculate very complex 3D structures and environments and is good at large electrical dimensions. It is often used for modeling and simulation of aircraft electromagnetic performance. Sonnet, MoM method. I am not familiar with this one. SuperNEC, MoM method, requires the use of MatLab platform. This will limit its calculation speed, because MatLab is a line interpreter and the code is not compiled. ADF-EMS is a software suite I just heard about. It is a product of an Italian company and was previously banned from export to China. It is said that it is too professional and useful, and is a powerful tool for electromagnetic simulation of spacecraft, satellites, weapons, etc. Now it is gradually being opened to Chinese companies. However, if a research institute or a state-owned institution wants to buy it, it is still not sold. The price is more than 10 times that of ANSoft and other suites. Aplac, it is said that Nokia people use it for electromagnetic field simulation. I have only contacted one of their sales and read some information, mainly about circuit and system level. The electromagnetic field module is fdtd, and the modeling is very complicated. I don't know anything else. CFDTD, full name Conformal FDTD, is a commercial package developed by Chinese. It is said that it has good reviews in the industry. However, it seems that the commercial performance is not good, and there is no news about it online. Needless to say, its feature is conformal. Now whoever can do a good job of conformal meshing of metal surface boundaries has a good calculation method.
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